Quick coupling for the drum of a duplicating duplicator

ABSTRACT

Duplicating machine having a drum rotatably mounted between a pair of side frames. Drum has a cylindrical wall having perforations communicating with an internal ink reservoir. An open mesh screen is stretched about the drum to provide an external cylindrical auxiliary reservoir immediately beneath an ink-distributing pad. Copy sheets are fed from a stack by adjustable pressure feed wheels and advanced along a path of movement to a first bight between a pair of forwarding rollers, and then to a second bight between an impression roll and the drum. Flexible paper strippers positively guide sheets to and from the drum, and are held out of wearing contact against stencil by raised peripheral rings at ends of drum. A pair of independently pivotal brackets support the ends of the impression roll and are spring-biased to press the impression roll toward the drum. Two transverse springs on each bracket are swingable to adjust the pressure of the impression roll on the drum. Impression roll is releasable without tools by manual endwise movement. A pivotal latch shaft has a pair of catch levers at opposite ends and radial paper sensing means intermediate them. The latch shaft is pivotable to and from a latching position wherein the brackets are engageable with the catch levers to hold the impression roll spaced from the drum and the paper sensing means across the path of movement between the first and second bights in the absence of a copy sheet. A cam, rotatable with the drum once per revolution, moves a rigid pivotal actuating frame and this in turn moves both brackets simultaneously to shift the impression roll away from the drum and to free the brackets and catch levers from frictional engagement with one another. Paper stop means is provided behind the forwarding rollers. Catch levers, controlled by the paper sensing means, hold the impression roll away from the drum in the absense of paper. Movements of parts and paper are synchronized enabling the cam to disengage the brackets from the catch levers as a sheet approaches the paper sensing means, and continued advance of the sheet against the paper sensing means swings the catch levers out of the way to enable the impression roll to press the sheet against a stencil on the drum. A single manually rotatable shaft connects and disconnects the drum. A quick release stencil clamp on the drum has a knife edge for removing the cover sheet from an underlying stencil. A manually releasable anchor enables quick, clean ink pad changes.

'United States Patent [19] Springer [451 Oct. 7, 1975 [54] QUICKCOUPLING FOR THE DRUM OF A DUPLICATING DUPLICATOR [75] Inventor: EdwardM. Springer, Chicago, Ill.

[73] Assignee: Heyer Inc., Chicago, Ill.

[22] Filed: May 13, 1974 [21] Appl. No.: 469,095

Related US. Application Data [62] Division of Ser. No. 186956, Oct. 6,1971, Pat. No.

[52] US. Cl 101/116; 101/141 [51] Int. Cl. B41L 13/06 [58] Field ofSearch 101/116, 118,132, 132.5,

101/141, 150, 153, 212, 216, 375, 127.1, 128.1; 118/DIG. 15; 301/124 R[56] References Cited UNITED STATES PATENTS 2,152,561 3/1939 Nigra101/116 2,605,701 8/1952 Huebner... 101/216 3,205,814 9/1965 Huck101/216 3,721,188 3/1973 Jacobsen et al..' 101/375 Primary Examiner.l.Reed Fisher Assistant Examiner-R. E. Suter Attorney, Agent, orFirm-McCaleb, Lucas & Brugman [57] ABSTRACT forwarding rollers, and thento a second bight between an impression roll and the drum. Flexiblepaper strippers positively guide sheets to and from the drum, and areheld out of wearing contact against stencil by raised peripheral ringsat ends of drum. A pair of independently pivotal brackets support theends of the impression roll and are spring-biased to press theimpression roll toward the drum. Two transverse springs on each bracketare swingable to adjust the pressure of the impression roll on the drum.Impression roll is releasable without tools by manual endwise movement.A pivotal latch shaft has a pair of catch levers at opposite ends andradial paper sensing means intermediate them. The latch shaft ispivotalble to and from a latching position wherein the brackets areengageable with the catch levers to hold the impression roll spaced fromthe drum and the paper sensing means across the path of movement betweenthe first and second bights in the absence of a copy sheet. A cam,rotatable with the drum once per revolution, moves a rigid pivotalactuating frame and this in turn moves both brackets simultaneously toshift the impression roll away from the drum and to free the bracketsand catch levers from frictional engagement with one another. Paper stopmeans is provided behind the forwarding rollers. Catch levers,controlled by the paper sensing means, hold the impression roll awayfrom the drum in the absense of paper. Movements of parts and paper aresynchronized enabling the cam to disengage the brackets from the catchlevers as a sheet approaches the paper sensing means, and continuedadvance of the sheet against the paper sensing means swings the catchlevers out of the way to enable the impression roll to press the sheetagainst a stencil on the drum. A single manually rotatable shaftconnects and disconnects the drum. A quick release stencil clamp on thedrum has a knife edge for removing the cover sheet from an underlyingstencil. A manually releasable anchor enables quick, clean ink padchanges.

11 Claims, 30 Drawing Figures I92 214 25a 2 264 292 194 19a llll 3i:1ll.'.3i?

US. Patent 0012. 7,1975 Sheet 1 of 13 3,910,184

llxlllliil'r Sheet 2 of 13 3,910,184

US. Patent O ct. 7,1975

U.S. Patent Oct. 7,1975 Sheet 3 0f 13 3,910,184

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US. Patent Oct. 7,1975 Shet4 of 13 3,910,184

Sheet 5 of 13 3,910,184

Oct. 7,1975

U.S. Patent US. Patent 00:. 7,1975 Sheet 8 of 13 3,910,184

Sheet 9 of 13 U8. Patent OCt. 7,1975

US. Patent Oct. 7,1975 Sheet 10 0f 13 3,910,184

Fig. 19

US. Patent Oct. 7,1975 Sheet 12 of 13 3,910,184

U.S. Patent Oct. 7,1975 Sheet 13 of 13 3,910,184

QUICK COUPLING FOR THE DRUM OF A DUPLICATING DUPLICATOR BACKGROUND OFTHE INVENTION This application is a division of mycopending applicationSer. No. 186,956, filed Oct. 6, 1971 now U.S. Pat. No. 3,835,772 forCompensating Impression Roller Mount For Stencil Duplicator.

The field of the invention is generally that of ink-type duplicatingmachines in which ink is transferred from the interior of a drum,through an ink pad and a stencil carried by the drum, onto copy sheets.

In such machines the copy sheets are fed, one at a time, from a stack,through a bight between the drum and an impression roll which pressesthe sheet against the stencil as it is drawn through the bight. Theimpression roll must not be pressed against the ink-covered stencil orit will smear the stencil and transfer ink to the backs of succeedingsheets. Mechanism must therefore be provided for preventing contactbetween the impression roll and the stencil when no sheet is fed to thedrum. Providing such mechanism is complicated because the presence of arelatively fragile copysheet must be sensed to trigger the verysubstantial forces required for moving the impression roll to press thecopy sheet against the stencil. A further complication is that modernduplicating machines must produce more than lOO copies per minute, sothere is very little time for the impression roll to be moved aftersensing the presence or absence of a sheet.

Machines of the type with which the present invention is concerned feedsheets in two separate movements with ,a definite stop or pause betweenthem. There is an initial movement of the sheet from the stack, followedby a final movement across the drum. It is important that this initialmovement be stopped at a definite point and at a definite timecorrelated with the rotation of the drum, to properly register theprinting on the sheet. Prior machines have not precisely controlled suchstopping and starting of the sheets resulting in a loss of precision inthe printed copy.

A problem, sometimes called dotting develops in conventional duplicatingmachines at high speeds, resulting for all practical purposes in anupper speed limit which will not produce acceptable copy. Conventionalduplicating machine drums have a cylindrical peripheral wall withperforations through which the ink flows to a pad, and thence to thestencil. At high speeds, ink flows more readily to the stencil portionsover the perforations than to the portions between, giving an uneven ordotted pattern to the printing.

Stencils vary in their ability to transmit ink, so it is necessary toprovide some mechanism for adjusting the pressure between the impressionroll and drum during printing.

The duplicating machines are relatively complicated, having many partswhich must be kept clean and in good operating order by regularmaintenance procedures. For this purpose it is important that the drumbe easily removable to provide access to parts beneath it.

Stencils commonly have a backing sheet which acts as a cushion duringtyping, and provides convenient means for handling as when assemblingthe stencil on a drum. After the stencil so assembled, the backing sheetis removed. Some stencils have a perforated line near the head portionalong which the backing sheet may be torn off. Others, such as certainelectronic stencils, do not have such a perforated line and the operatorhas to tear the backing sheet along a ruler or other separate straightedge tool held against the drum. This is not completely satisfactorybecause the operator must hold the tool by one hand, aligned by eye, andthe resulting torn edge is often crooked.

SUMMARY OF THE INVENTION A principal object of the present invention isto provide an ink-type duplicating machine which functions withprecision at high speeds and can be manufactured in volume at areasonable cost.

A specific object is to provide mechanism controlled by a singlemanually operable knob or shaft for connecting the drum into andreleasing it from the machine.

Other objects and advantages will be apparent from the followingdescription taken in connection with the drawings in which:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of amachine illustrating the present invention, the figure showing sideornamental plates or covers which enclose certain operative parts of themechanism;

FIG. 2 is a partial plan view of the machine shown in FIG. 1;

FIG. 3 is a partial vertical section taken on line 3--3 of FIG. 2;

FIG. 4 is an enlargement of a portion of FIG. 3;

FIG. 4A is an external fragmentary view of the drum as seen in thedirection of arrows 4A4A in FIG. 4;

FIG. 5 is a side elevation of the driving and timing mechanism viewedalong line 5-5 of FIG. 2, but with the respective ornamental coverremoved;

FIG. 6 is an enlargement of a portion of FIG. 5; FIG. 7 is a perspectiveview of the printing drum and some associated parts removed from themachine;

FIG. 8 is an enlarged fragmentary cross-sectional view of FIG. 7 takenalong the line 8-8;

FIG. 9 is an enlarged fragmentary longitudinal crossectional view takenalong line 9-9 of FIG. 2 showing mechanism operated by a single shaftand knob for I connecting and disconnecting the drum in the machine;

FIG. 10 is a sectional elevational view taken gener-' ally along line10-10 of FIG. 2, with certain parts removed showing the relationship ofcertain components as a copy sheet is fed forward to begin the printingcycle;

FIGS. 1116 are schematic views similar to FIG. 10 but on a reduced scaleshowing subsequent operative positions of components as the copy sheetis advanced through the machine;

FIG. 17 is a perspective view of certain parts of the mechanism;

FIG. 18 is an enlarged fragmentary view of FIG. 17 along line 18-18;

FIG. 19 is a fragmentary view of FIG. 5 with the side frame removed toshow one of the brackets which supports the impression roll and showingthree adjusted positions of the spring biasing means;

FIG. 20 is an enlarged sectional view of FIG. 19 taken along line 20-20;

FIG. 21 is a view similar to FIG. 20 showing the impression rollpartially disconnected;

FIG. 22 is a fragmentary view of FIG. 5 showing the mechanism forsupporting and moving one of the forwarding rollers, with the bightbetween the rollers being shown in open condition; I

FIG. 23 is a fragmentary view similar to FIG. 22 but showing the bightbetween the rollers closed;

FIG. 24 is a plan view partly in section of the mechanism shown in FIGS.22 and 23;

FIG. 25 is an enlarged view of a portion of FIG. 24;

FIG. 26 is a perspective view showing the drum connected to a removablecarrying bailfor transfer to a storage stand;

FIG. 27 is a view of the bailand drum supported on a storage standremote from the duplicating machine;

FIG. 28 is a fragmentary perspective view .of the drum supported on thestorage stand; and

FIG. 29 is a fragmentary view of FIG. 28 showing the details of theshoulder and rib arrangement for supporting the drum.

DESCRIPTION OF THE PREFERRED EMBODIMENT The machine shown in thedrawings comprises a housing 30 havinga pair of side plates or frames 32and 34; a feed table or tray 36 for supporting a stack 63 of copy sheets64 in position to be advanced into the housing; feed means 38 foradvancing sheets from the stack; a pair of relatively movable forwardingrollers 40 and 42 defining a first, variable bight 358 therebetween; arotatable drum 44; an impression roll 46 movable relative to the drumand defining with the drum a second, variable bight 360 and guide meansincluding lower and upper guide plates 362 and 364 and strippers 375 forguiding copy sheets along a path of movement from the tray through thefirst and second bights. Paper stop means 54 and papersensing means 56are disposed along the path of movement between the first and secondbights.

Referring now in more detail to the above mentioned components and theircooperation in the machine, the side plates 32 and 34 are held in fixedspaced relationship by a number of rigid cross members bolted orotherwise fastened therebetween. These include transverse struts 58 and60, rod 62, and other elements forming part of the housing.

The feed table 36 is shown and described in detail in Springer US. Pat.No. 3,417,988 issued Dec. 24, 1968 on Sheet Guiding Mechanism. Briefly,it supports a stack 63 of copy sheets 64 at the input end in position tobe advanced one at a time into the housing. The operation is automatic,the rate of feed being one sheet per each rotational cycle of the drum.At the output end of the machine is a receiving tray 66 to collect theprinted sheets.

Feed means 38 conprises a pair of rubberlike feed wheels 68 slidable todifferent spacings along a shaft 70 for sheets of different widths. Theends of the shaft 70 are rotatably journaled in a pair of arms 72 whichare pivoted for up and down swinging movement outside the respectiveside plates 32 and 34, about the aligned axes of two separate shafts 74.The arms 72 have upwardly offset sections 76 held by bolts 78 to theends of a spacer rod 80. An arcuate slot 81 in each side plate providesclearance for the shaft 70 and rod 80 during up and down movements ofthe feed wheels 68.

As shown in FIG. 5, the end of shaft 70 adjacent the side plate 32 isconnected through an overrunning clutch 82 to an outer race 86 havingexternal gear teeth 88. An inner race 84 is fixed to shaft 70, andsprags (not shown) between the inner and outer races drive shaftcounterclockwise when the outer race rotates counterclockwise as seen inFIG. 5. The sprags overrun or free wheel when the outer race rotatesclockwise.

, The outer race 86 is rotatably driven by a train of gears 90 and 92carried by the respective arm 72. Gear 90 is rotatable on shaft 94 whichis mounted on arm 72 intermediate its ends. Gear 92 is rotatable onshaft 74.-

Both gears 90 and 92 are held in place by snap rings 96. Thus. it willbe seen that the train of gears for driving feed wheels 68 swingvertically with pivotal movement of shaft 74, allowing the feed wheelsto move down as the stack of sheets on the feed table is used up duringoperation of the machine.

The upper and lower forwarding rollers 40 and 42 have a series ofrollers 98 and 102 on shafts and 104 respectively. I

The ends of shaft 100 are rotatably journaled in side plates 32 and 34.Externally of side plate 32, as shown in FIG. 5, shaft 100 is connectedto an inner race 106 of an overrunning clutch 108. The outer race 110has external gear teeth meshed with both gear 92 and gear sector 112.Sprags (not shown) between the inner and outer races enable the shaft100 to be rotated by the outer race only in a counterclockwise directionas seen in FIG. 5. Clutch 108 overruns when its outer race rotatesclockwise.

At the other end of shaft 100, exteriorly of side plate 34, there is afriction brake generally designated 114 (FIGS. 17 and 18). Thiscomprises a flexible friction strap 116 having a riveted loop 118anchored to a stub shaft 120 on the exterior of side plate 34. Strap 116has a bend 122 tensioned about a flat cylindrical groove 124 at the endof shaft 100 by a spring 126 held by pin 128 on side plate 34. Thisholds the shaft 100 braked against rotation unless the shaft ispositively driven by a torque sufficient to override the friction ofstrap 116 against the brake groove 124.

As best shown in FIGS. 2225, the ends of lower forwarding roller shaft104 are loosely rotatably journaled in bearings 128 carried by levers130. The levers 130, together with the shaft 104, comprise a flexibleactuated frame for supporting the annular roller elements 102. The loosejournal connection represented by the clearance between each bearing 128 and shaft extension 129 (FIG. 25) comprises in effect a limitedlyswivelable connection enabling the ends of the shaft 104 to move up anddown independently of one another, within limits, thereby enabling theends of the lower forwarding roller assembly 42 to press uniformlyagainst the upper forwarding roller assembly 40.

Each lever 130 has an integral boss 131 at its midsection pivoted forrocking movement about a reduced end portion 133 of an actuating shaft132. Each end portion of shaft 132 is rotatably journaled in a bushing134 in one of the side plates 32 and 34. The shaft 132 comprises part ofa rigid actuating frame including actuating levers 136 which are held byscrews 138 to T- handle 139 fast to the reduced diameter extension 133.A washer 141 is provided between members 131 and 139.

Each lever 136 has an inwardly extending transverse pin engageableedgewise with the end portion of the corresponding lever 130 oppositethe end portion carrying the shaft 104.

A tension spring 142 is connected between pin 140 and an anchor pin 44on side plate 32. This biases the rigid actuating frame (shaft 132 andlevers 136) coun terclockwise as viewed in FIGS. 22 and 23.

Two springs 146, both external of side plates 32 and 34, are connectedbetween an anchor opening 148 in each lever 130 and an anchor pin 150 onside plate 32 or 34. Springs 146 exert a torque on the flexibleactuating frame (shaft 104 and levers 130) urging the movable lowerforwarding roller assembly 42 upward against the fixed upper forwardingroller assembly 40. Both the actuating and actuated frames referred toare thus biased counterclockwise (FIGS. 22 and 23) about the same shaft,namely shaft 132.

At the end of shaft 132 exteriorly of side plate 32 (FIG. 24) lever 136has an opposite extension arm 152 with a follower roller 154 engageablewith a cam for automatic operation to be described.

There is a lost motion relationship between levers 130 and 136 on bothsides of the housing. This effectively enables the lower forwardingroller assembly 42 to be moved downward as a unit, but allows the endsof roller assembly 42 to seek their own positions when moved upwardlyfor the best, uniform engagement with roller assembly 40. This lostmotion arrangement is best shown in FIG. 23. There, shaft 132 and lever136 are rotated counterclockwise sufficiently to disengage pin 140 fromthe lower edge 156 of actuated arm 130. This, of course, would be trueon both sides of the ma chine. Because the shaft 104 and levers 130comprise a limitedly flexible frame, each spring 146 moves eachcorresponding lever 130 in a direction to close the first bight 358,between the rollers 40 and 42, on each side of the machine as shown inFIGS. 3 and 23. When the integral actuator arm 152 and lever 136 arerocked clockwise about the axis of shaft 132, both pins 140 will engagethe under edges 156 of arms 130, rotating the latter clockwise (FIGS. 22and 23) about shaft 132 and opening the bight between rollers 40 and 42.This opened bight is shown in FIG. 22.

Returning now to the description of the synchronized drive mechanism forthe feed wheels 68 and forwarding rollers 40 and 42, the drum 44 isdriven by a motor 158. As shown in FIGS. 7, 8 and 9, the drum, in turn,then drives the feed wheels and forwarding rollers.

The drum 44 comprises a pair of circular ends or heads 160 and apartially cylindrical peripheral wall 162 having apertures 164. An openmesh screen 166 covers the wall portion 162 and, as will be described,provides an auxiliary, cylindrical ink reservoir immediately beneath anink pad 168 for instant access of ink thereto. Such auxiliary inkreservoir receives ink through the apertures 164 from a main inkreservoir 170 within the drum.

The apertured cylindrical wall section 162 shown in FIGS. 7 and 8 is theprinting portion of the drum which supports the ink pad 168 and astencil 547. Between the leading edge 172 and the trailing edge 174(FIG. of the cylindrical printing segment 162, there is a recess 176defined by an ink retaining wall 178 having a threaded cap 180 throughwhich ink is put in the main reservoir 170. The recess 176 also containsink pad clamp means 182 and stencil clamp means 184 both of which willbe described in detail.

Each drum end or head 160 has a generally rectangular reinforcing plate186 (FIGS. 7, 8 and 9) affixed thereto as by soldering or brazing.Plates 186 are parallel and each has an outer eccentric lug 188 and apair of circumferentially spaced lugs 190 disposed closer to therotational axis of the drum. As will be described, there is a lug 188 ateach end of the drum. These provide convenient temporary anchor pointsfor a carrying bail, to move the drum back and forth between the machineand a separate storage stand. The two pairs of lugs 190 at opposite endsof the drum 44 provide means for transmitting torque between the drum 44and supporting members 218 and 236, and they enable initial, positivealignment of the drum 44 and supporting members 218 and 236 along theircommon rotational axis before they are connected together, and therebymake it possible to rapidly connect and disconnect the drum within themachine. To avoid inadvertent reversal of the drum within the machine,the opposite pairs of lugs 190 may be located at different radialdistances from the center.

Referring to FIG. 9, an axial sleeve or tube 192 is soldered or brazedbetween the ends of the drum. Within the sleeve is an axially shiftableshaft 194 and an internally threaded bushing 196 which is fixed inposition by soldering or brazing to the interior surface of sleeve ortube 192. The shaft has an inner extension 198 of sufficiently reduceddiameter to clear the threaded bore of bushing 196. A guide washer 200is supported on the extension 198 and is slidable within the bore ofsleeve 192. A coil spring 202 is compressed between an internal snapring 204 in a groove at one end of the sleeve 192, and an external snapring 206 in a groove on shaft 194. The spring biases the shaft 194 tothe right (FIG. 9), toward a position wholly contained between the endsof the sleeve 192. In this position the washer 200 engages the bushing196 and serves as a stop for the shaft 194.

The mechanism for supporting the drum 44 between the side plates 32 and34 will now be described.

A supporting and driving tube 208 is rotatably journaled within a sleevebearing, 210 in side wall 34. A drive pulley 212 is fastened to thesupporting tube 208 in any suitable manner as for example by the setscrew 214. A flanged hub 216 is fastened to the end of supporting tube208 interiorly of the side plate 34, by solder or a press fit. Adisc-like supporting member 218 is fastened to the hub 216. An alignmentand driving member 220 is fastened as by rivets 222 to the insidesurface of supporting member 218. As best shown in FIG. 7, the member220 is T-shaped, having radially outwardly facing ledges or shoulders226 for supporting the lugs to axially align the drum sleeve 192 withthe supporting tube 208. Lugs 190 are spaced sufficiently to straddlethe rib or stem portion 224 of the T-shaped member 220 and therebyprovide an effective rotatable driving connection between the supportingdisc member 218 and the drum.

A second supporting and driving tube 228 (comprising a substantialcounterpart of supporting tube 208) is rotatably journaled within asleeve bearing 230 fixed within side plate 32. A center shaft 232 isrotatable with supporting tube 228 and has an end bore 233 positioned toreceive the outer end portion 264 of shaft 194 when extended as shown inFIG. 9.

A flanged hub 234 (similar to 216) is fastened to the inner end ofcenter shaft 232 and is rotatable with that shaft and with supportingtube 228 in normal operation. A disc-like supporting member 236, whichmay be identical with member 218, is connected to the flanged hub 234and rotatable therewith. A T-shaped locking member 220 and lugs 190, asdescribed above for the other end of the drum, provide a releasable,rotatable driving connection between the supporting disc member 236 andthe drum. A cam 238 is fastened to and rotatable with the sleeve 228.Cam 238 moves the impression roll 46 relative to the drum by mechanismwhich will be described.

By a worm and pinion means not forming part of the present invention,and therefore not shown, the tube 228 and 232 are rotatably adjustableto vary the cam 238 relative to the drum. This raises or lowers theprinting on the copy sheets in response to rotation of adjusting discs239 on wheel 241 (FIG. 1).

Externally of the side plate 32 a drive bushing 240 is fastened to thesupporting tube 228 by a set screw 242. Fastened to the drive bushing240 and rotatable therewith is a drive gear 244 and cams 246 and 248. Aswill be described, cam 246 moves the paper stop means 54, and cam 248(fastened to 246 by spacer rivets 250) moves forwarding roller 42.

As shown in FIG. 3, the power source for the machine is the motor 158.This is connected through a suitable speed reducing power transmission(not shown) to drive pulley 212 shown in FIG. 9. Optionally, for a moresimplified, less automatic version of the ma chine, one of the tubes 208and 228 may be turned by a hand operable crank not shown.

Thus, rotation of tube 208 by the drive pulley 212 (or the optionalcrank) rotates supporting drive disc member 218. This rotates the drumand the other supporting drive disc member 236 through the two sets ofT- shaped locking members 220 and lugs 190. Dics 236 drives tube 228 andthe parts rotatable therewith including drive gear 244 and cams 246 and248.

Having described the parts for supporting the drum, the means operatedby a single handle for quickly con necting and disconnecting the drumbetween the sideframes will now be described.

Refer again to FIG. 9. A shaft 252 having a reduced diameter outerextension 254 is rotatable, and axially slidable, within supporting tube208. A knob or handle 256 is held by a set screw 258. A snap ring 260 inan internal groove in tube 208 retains the shaft 252.

At its extreme inner end, shaft 252 has an externally threaded reduceddiameter extension 262, adapted to be screwed into bushing 196 as shownin solid lines in FIG. 9.

To disconnect the drum, the knob 256 need only be rotated sufficientlyto disconnect threaded extension 262 from threaded bushing 196. Then, bydrawing the handle 256 outwardly from the tube 208 until the outershoulder of shaft 252 engages the snap ring 260, the threaded inner endportion 262 will be moved to the broken line position shown in FIG. 9,disconnecting the right end of the drum at hub 216. As the shaft end 262moves away from the extension 198 of shaft 194, the latter will shiftautomatically to the right (FIG. 9) until its outer end 264 is recessedwithin the end of the drum as shown in broken lines. This releases theleft end of the drum at hub 234. Then, with the drum rotated so thelocking members 220 are upward, the drum can be lifted straight upward,free of the machine.

Conversely, the drum 44 (or another drum with different colored ink) maybe assembled quickly by lowering the drum into position for engagementof the lugs 190 with the locking members 220, followed by pressing theshaft 252 inward and turning handle 256 to engage locking means herecomprising the screw threads in members 196 and 262.

When the shaft 194 is completely retracted by the spring 202 into thedrum, the reduced diameter inner end 198 is positioned slightly to theright of the threaded bushing 196. This is shown in broken lines in FIG.9. This permits initial inward movement of the shaft 252 to engage theend 198 of shaft 194 and shift the opposite end 264 into bore 233 inshaft 232 before the threads in members 262 and 196 are engaged. Theassembly can then be moved to the solid line locked position shown inFIG. 9 by only one or two subsequent turns of the knob 256.

By the foregoing, the drive from motor 158 to the drive gear 244 hasbeen described. The driving connections from gear 244 to the sector 112will now be described to complete the driving train for the machine.

Drive gear 244 rotates crank gear 266 about pin 268 fastened to sideplate 32. Crank pin 270 is connected by lever 272 to the midpoint oflever 274 which rocks back and forth about pin 276 fastened to sideplate 32. Lever 274 is held to pin 276 by snap ring 278. At the free endof lever 274 a pin 280 is engaged with an arcuate slot 282 in sector112. The sector is rockable about a pin 284 fastened to side plate 32and a snap ring 286 holds it in place.

The sector has an arcuate line of gear teeth 288 meshed with gear teeth290 on the outer race of overrunning clutch 108 which has previouslybeen described.

Cyclic rotation of feed wheels 68 and forwarding rol ler 40 may now besummarized as follows. Rotation of crank gear 266 causes crank lever 272to rock lever 274 back and forth. This alternately rocks gear sectorteeth 288 clockwise, and counterclockwise, about shaft 284. Because ofthe overrunning clutches 82 and 108, previously described,counterclockwise movement (FIG. 5) of sector 112 rotatably drives thefeed wheels 68 in a counterclockwise direction to feed the top sheet 64from the stack on the feed table 36; at this time, the clutch 108 isoverrunning and therefore not driving the forwarding rollers. Next, whensector 112 rocks in a clockwise direction, overrunning clutch 108 drivesthe upper forwarding roller in a counterclockwise direction to furtheradvance the sheet toward the drum. These separate advancing movements ofthe sheet by the feed wheels and forwarding rollers are synchronizedwith operation of the other parts of the mechanism as will be described.

As shown in FIGS. 17 and 19, the impression roll 46 is carried by ashaft 292 having its opposite ends respectively journaled in brackets294, 294 which are independently pivotable about stub shafts 296extending inwardly from side plates 32 and 34. The detailed constructionof the mounting enabling the ends of the shaft 292 to be rotatablyjournaled in the brackets 294, yet sufficiently pivotal to enable thebrackets to move up and down independently, is best shown in FIGS. 17,19, 20 and 21 and will be described subsequently.

Each bracket 294 has an elongated body portion 320 and an out-turnedflanged portion 322. The body portion has a pivot opening 324 engagingpivot shaft 296, and a catch pin 326 on the outer side of the bracket atthe end remote from pivot shaft 296. Each bracket has interruptedelongated slot means consisting of a pair of horizontal, aligned slots328 and 330, the latter having three detent notches 332, 334 and 336 inthe upper edge.

An adjustment member 338 is manually movable lengthwise along eachbracket to vary the pressure of the impression roll against the drum.Each adjustment member includes an elongated body portion 340 and aninturned grip portion 342 and each has a pair of pins 344 and 346engageable respectively within the slots 328 and 330. The pins haveenlarged heads 348 to keep them within the slots.

A tension spring 350 is connected between pin 344 and an anchor pin 352on the adjacent side plate 32 or 34. Similarly a tension spring 354 isconnected between pin 346 and an anchor pin 356 on each side plate. Asshown in FIGS. 17 and 19, the lines of action of springs 350 and 354extend substantially parallel to the vertical planes of movement of thebrackets 294. Further, the lines of action of these springs aretransverse to the lines of adjustment movement of the adjustment members338.

In the embodiment disclosed, the adjustment members 338 are movable tothree different torque positions to select three degrees of pressure ofthe impression roll against the drum. When pins 346 are in notches 336,the lines of action of the springs 350 and 354 will be at a maximumdistance from the pivot pin 296, and the combined upward pull of thesprings to exert torque to the brackets and press the impression rolltoward the drum will be at the maximum. When pins 346 are in middlenotches 334, as shown in solid lines in FIG. 19, the lines of action ofthe springs will be somewhat closer to the pivot shaft 296, and thetorque on the brackets and the upward pressure of the impression rollagainst the drum will be at an interme diate value. When pins 346 are innotches 332, the line of action of spring 354 will be on the oppositeside of pivot shaft 296 (see FIG. 19) so that only springs 350 willexert any effective torque and upward pressure on the impression roll.Thus, each adjustment member 338 is movable between a maximum torqueposition where pin 346 is seated in notch 336, and a minimum torqueposition where pin 346 is seated in notch 332.

An important feature of the machine is the mechanism enabling theimpression roll 46 to be connected quickly and easily into the machine,or to be disconneeted therefrom. This is best shown in FIGS. 17, 19, 20and 21.

The impression roll comprises a resilient cylindrical cover 351concentrically mounted on shaft 292. The ends of shaft 292 have reduceddiameter extensions 353 and 355. A snap ring retainer or stop 357 isprovided in a groove at the end of each extension. Sleeve bearingmembers 359 and 361, which may be identical, and each having an externalflange 363, are slidably mounted on extensions 353 and 355,respectively. A coil spring 365 on extension 353 is seated between ashoulder 367 and the flange of bearing member 359, biasing the latter inan outward direction. At the other end of shaft 292, a rotatable washer369 is interposed .7 between shoulder 371 and the flange of bearingmember 361.

In operating position, the impression roll 46 is assem bled withbearings 359 and 361 seated within openings '373 in the brackets 294 asshown in FIG. 20.

drawing bearing 361 from opening 373, as shown in FIG. 21. So released,the impression roll may simply be pivoted about its remaining engagedend and swung out of the machine. The snap ring retainers 357 functionas stops to limit outward movement or loss of the bearing members whenthe impression roll is removed from the machine.

As described, it is important that the brackets 294 be free to pivotindependently, to the extent that opposite ends of the impression rollwill be pressed uniformly against the drum. The ends of the shaft 292must, of course, rotate within the bearings 359 and 361 and the bearingsmust allow for limited pivotal movement of the ends of the shaftrelative to the brackets. This is provided simply and practically in thepresent invention by making the clearances between the bearings and theshaft, and between the bearings and the brackets large enough to allowsuch combined rotational and pivotal movement.

As shown in FIG. 3, guide mechanism is provided for guiding copy sheets64 successively along a path of movement from the stack 63 on the feedtable 36 to the first bight 358 (between the forwarding rollers) andthen to the second bight 360 (between the impression roll and the drum).This guide mechanism includes lower and upper supporting and guideplates 362 and 364. The guide plates extend between the side plates 32and 34 and have transverse flanges fastened thereto by bolts 366 and368.

The lower supporting and guide plate 362 includes a vertical wall 370with studs 372 for engaging the feed table 36, an upwardly inclined wall374, and a lower horizontal wall 376 extending along and below the pathof movement of the sheets. The upper supporting and guide plate 364includes a downwardly inclined wall 378 and an upper horizontal wall 380extending along and above the path of movement of the sheets. Horizontalwall portions 376 and 380 have openings 382 and 384 for the individualfollower roller elements 102 and 98 respectively.

The paper stop means generally designated 54 comprises a transverselyextending plate having an up wardly inclined portion 386 terminating invertical fingers 388 which extend through openings in the lowerhorizontal guide wall 376 when in their fully raised position (FIG. 10).The stop plate is fastened as by screws 390 to rock shaft 392 which ispivoted between the side plates 32 and 34.

As best shown in FIG. 5, a paper stop actuating lever 394 is connectedto rock shaft 392 externally of the side plate 32. The upper end oflever 394 has a follower roller 396 engageable with cam 246 alreadydescribed in connection with FIG. 9. The lower end of lever 394 isconnected by a spring 398 to an anchor pin 400 on side plate 32 andbiases the lever 394 in a clockwise direction to keep follower 396engaged with the cam 246.

Another important part of the invention is springtype paper strippermeans functioning as an extension of the upper supporting and guideplate 364. This feature is best shown in FIGS. 2 and 3.

As shown in FIG. 2, the axial length of the drum 44 exceeds that of theimpression roll 46. A pair of transversely spaced, flexible strips 375of material such as spring steel are fastened by bolts 377 to the top ofthe inclined wall 378. The strips 375 extend in an outward directionover the end of the upper horizontal guide wall 380, tangent to thebottom of the drum as shown in FIG. 3, to anchor pins 379 on the sideframes. Thus. the stripper strips 375 will positively guide a sheet tothe drum and then positively strip it from the bottom of the drum itpasses beyond the second bight by reason of the fact that the strips 375extend continuously from the end of horizontal guide wall 380 to aposition well beyond the second bight 360.

Each axial end portion of the drum has a peripheral ring 381 providing aslightly raised circumferential sur face engaging the strips 375 andkeeping them out of wearing engagement with a stencil on the drum.

An important feature of the strips 375 is that because they are mountedon top of and substantially upstream of the edge of horizontal guidewall 380, they continuously engage the edges of a copy sheet to,through, and beyond the second guides This guiides the sheet to thedrum, and positively strips it from the drum after printing.

Mechanism will now be described for moving the impression roll 46 towardand away from the drum and for holding the impression roll out ofcontact with the drum when the machine operates without paper passingthrough it.

A rigid actuating frame, generally U-shaped and designated 399 (FIG. 17)is interposed between the single cam 238, (previously described inconnection with FIG. 9) and the two independently movable brackets 294.The rigid actuating frame consists of a countershaft 401 pivotallyjournaled in side plates 32 and 34, and a pair of actuating arms 402which extend toward the brackets 294. Each arm 402 has a lower roller404 engageable with the top edge 406 of a corresponding bracket. One ofthe arms 402 has a follower roller 408 engageable with cam 238previously described in connection with FIG. 9. A tension spring 410(FIGS. 3 and 17) hold the rollers 404 engaged with bracket edges 406.This promotes quiet operation.

Because the actuating frame 399 is rigid, downward movement of eitherarm 402 is accompanied by identical movement of the other arm. Thus, inspite of the fact that both brackets 294 are independently movable topromote uniform upward pressure of the impression roll against the drum,both ends of the impression roll will be moved simultaneously downwardlyfrom the drum when the high portion H of cam 238 engages follower roller408. The part of the mechanism which holds the impression roll 46 out ofcontact with the drum in the absence of a copy sheet will now bedescribed. A latch shaft 412 is pivotally journaled between the sideplates 32 and 34. A pair of identical catch levers 414 are mounted atthe ends of the latch shaft. Paper sensing means 56 comprise radialfingers 416 carried by latch shaft 412 intermediate its ends.

The paper stop fingers 388 and the paper sensing fingers 416 are bothalong the path of movement of the copy sheets between the first andsecond bights as shown in FIG. 3.

The latch shaft 412 is pivotable between a latching position and anunlatching position. In the latching position shown in FIGS. 10 and 17,the catch levers are swung to a substantially vertical position withtheir notches 420 engaging bracket catch pins 326 to hold the brackets294 in position to keep impression roll 46 out of contact with the drum.In the unlatching position, shown for example in FIGS. 14, and 16, the

catch levers 414 are swung free and enable the spring urged brackets tomove the impression roll upward and press a copy sheet against a stencilon the drum.

Ornamental covers 422 and 424 (FIG. 1) are provided to cover themechanism above described which is on the external surfaces of the sideplates 32 and 34. A hand wheel 241 is connected with supporting tube 228(by means not shown) and adjusting wheel 239.

may be rotated in one direction of the other and (by means not shown)may rotate shaft 232 relative to supporting tube 228 to advance orretard the cam 238 relative to the supporting disc 236. This is no partof the present invention so will not be described in detail, but,briefly, this adjustment raises or lowers the location of printing onthe copy sheet, as previously described.

An important part of the invention, facilitating the uniformdistribution of ink over the copy sheet at high speeds is the open meshscreen 166 (FIG. 8) which is stretched permanently about the apertured,cylindrical peripheral wall portion 162 and comprises an integral partof the drum. This communicates via apertures 164 with the main interiorink reservoir 170 inside the drum. As the drum rotates ink isdistributed over the inside of the wall 162 and passes through theapertures 164 into the interstices of the open mesh screen 166 whichconstitutes in effect a continuous cylindrical auxiliary reservoirexternally of the wall 162.

The ink pad 168 will preferably have a flannel side fitted with the napextending into the screen 166 and with an exterior fine weave surface ofmaterial such as nylon or silk. Thus, by capillary action of the napfibers extending into the auxiliary reservoir, namely the screen 166,ink would be transferred rapidly and uniformly to the outer surface ofthe pad 168. This greatly inhibits dotting which occurs at high speedswith conventional drums having the ink pad directly on the aperturedperipheral wall 162. This dotting effect results where ink cannot flowto the pad areas between apertures 164 as readily as it flows throughthe areas directly over the apertures.

The ink pad 168 may be assembled quickly and easily on the screen 166utilizing the improvements of the present invention as follows.

Refer now to FIGS. 4 and 4A. The drum has an eye 430 fastened as byrivets 434 to each of the heads within the recess 176. Only one eye 430is shown, this being on the head illustrated in FIG. 4 and at the top ofFIG. 4A. These are near the leading end 172 of the cylindrical printingarea 162. At the other end of the recess 176, adjacent the trailing end174 of the cylindrical printing area 162 an angle member 436 isfastened, by a pair of bolts or rivets 428 attached to the floor plate178. The base plate 440 of angle member 436 is supported above the floorplate 178 by washers 439 which are seated on the floor plate 178 andwhich encircle the bolts or rivets 438. A second angle member 442 ismovable in the clearance between base plate 440 and floor plate 178.This movable second angle member 442 has a base plate 444 which isslidably retained in the above-mentioned clearance between plates 440and 178. Grooves 443 in the base plate 444 engage the washers 439 andguide the base plate for right and left movement as seen in FIG. 4A. Aleaf spring 446 is riveted to the center of movable base plate 444 andhas an upwardly inclined portion 448 extending through central openings452 and 453 in upstanding webs 441 and 445, respectively. A small up-

1. In a duplicating machine, means for connecting and disconnecting arotatable drum in a housing including: a pair of supporting members atthe ends of said drum journaled in said housing for rotation with saiddrum about a common axis; first and second shafts aligned along saidaxis, and carried respectively by one of said supporting members and bysaid drum; said first shaft being manually movable between an extendedposition connected with said drum, and a retracted position disconnectedfrom said drum; said second shaft being movable between an extendedposition connected with the other of said supporting members, and aretracted position disconnected from said other supporting member; meansfor moving said second shaft to its said extended position in responseto movement of said first shaft to its said extended position, andbiasing means, within said drum, effective to move said second shaft toits said retracted position in response to movement of said first shaftto its said retracted position; whereby movement of said first shaft inone direction connects said drum to both supporting members, andmovement of said first shaft in the opposite direction disconnects saiddrum from both supporting members.
 2. In a duplicating machine, thecombination of claim 1 in which biasing means within said drum includesa spring urging said second shaft toward its said retracted position,and said shafts are engageable for overriding said spring while movingsaid second shaft to its said extended position.
 3. In a duplicatingmachine, the combination of claim 2 including a lockable connectionbetween said first shaft and said drum effective when locked to holdsaid shafts in their said extended positions.
 4. In a duplicatingmachine, the combination of claim 1 in which: each of said rotatablesupporting members has a pair of circumferentially spaced radiallyoutwardly facing shoulders and a rib between said shoulders extendingradially outwardly therefrom; and each end of said drum has a pair oflugs circumferentially and radially spaced thereon to straddle said riband engage said shoulders on an adjacent supporting member when saiddrum and supporting members are in axial alignment, to facilitatealigning said drum with said supporting members before connecting saiddrum by said first and second shafts.
 5. In a duplicating machine, thecombination of claim 4 in which: a third lug is provided on each end ofsaid drum radially outwardly of said pair of lugs; and said third lugsat the opposite ends of said drum provide connections for a bail totransfer said drum between said housing and a separate storage standwhen said first and second shafts are in their said retracted positions.6. In a duplicating machine, means for connecting and disconnecting arotatable drum in a housing including: a pair of supporting members atthe ends of said drum journaled in said housing for rotation with saiddrum about a common axis; first and second shafts aligned along saidaxis, and carried respectively by one of said supporting members and bysaid drum; said first shaft being manually movable between an extendedposition connected with said drum, and a retracted position disconnectedfrom said drum; said second shaft being movable between an extendedposition connected with the other of said supporting members, and aretracted position disconnected from said other supporting member; meansfor moving said second shaft to its said extended position in responseto movement of said first shaft to its said extended position, andbiasing means within said drum effective to move said second shaft toits said retracted position in response to movement of said first shaftto its said retracted position whereby movement of said first shaft inone direction and in the opposite direction respectively connects saiddrum to and disconnects said drum from both supporting members; each ofsaid supporting members having a pair of circumferentially spacedradially outwardly facing shoulders and a rib between said shouldersextending radially outwardly therefrom; each end of said drum having apair of lugs circumferentially and radially spaced thereon to straddlesaid rib and engage said shoulders on an adjacent supporting member whensaid drum and supporting members are in axial alignment, to facilitatealigning said drum with said supporting members before connecting saiddrum by said first and second shafts; and a storage stand for supportingsaid drum separate from said housing having a pair of vertical supportarms extending upwardly from a base each arm having a pair of stationaryupwardly facing horizonal shoulders and a rib between said shoulderswhich are substantial counterparts of those on a corresponding one ofsaid rotatable supporting members.
 7. In a duplicating machine, meansfor quickly connecting and disconnecting a rotatable drum between a pairof side frames including: a pair of supporting members at the ends ofsaid drum journaled in said side frames for rotation with said drumabout a common axis of rotation; said supporting members having boresaligned along said axis of rotation; an axial sleeve in said drum; ascrew-threaded bushing within said sleeve; a first shaft, within thebore of one of said supporting members, axially shiftable between anextended position engaged within an end of said sleeve, and a retractedposition disengaged from said sleeve; a second shaft, within saidsleeve, axially shiftable between an extended position having an endportion engaged within the bore in the other of said supporting members,and a retracted position disengaged from the bore in said othersupporting member; and spring means within said drum urging said secondshaft toward its said retracted position; said first shaft having amanually operable handle at its outer end portion exteriorly of said onesupporting member, and a screw-threaded extension at its inner endportion; said first shaft, when moved to its said extended position,being engageable with said second shaft to shift said second shaft toits said extended position, and being rotatable to engage the threads ofsaid extension and bushing to hold said shafts in their respectiveextended positions, thereby simultaneously connecting both ends of saiddrum with said supporting members; said first shaft, when moved to itssaid retracted position, being disengageable from said second shaftenabling said spring means to shift said second shaft to its saidretracted position, thereby simultaneously disconnecting both ends ofsaid drum from said sUpporting members.
 8. In a duplicating machine,means for quickly connecting and disconnecting a rotatable drum within ahousing including: a pair of supporting members at the ends of said drumjournaled in said housing for rotation with said drum about a commonaxis of rotation; said drum having axial openings at opposite endsthereof; a first shaft, having an external handle, journaled in one ofsaid supporting members for axial movement through one of said axialopenings to and from a position engaged with said drum; a second shaft,journaled within said drum for axial movement through the opposite ofsaid axial openings to and from a position engaged with said othersupporting member; means for moving said second shaft through saidopposite axial opening in response to movement of said first shaftthrough said one axial opening, to thereby connect both ends of saiddrum simultaneously with said supporting members by means of saidshafts; and biasing means within said drum for moving said second shaftautomatically to a position wholly recessed within said drum in responseto withdrawal of said first shaft from said one axial opening, tothereby disconnect both ends of said drum simultaneously from saidsupporting members.
 9. In a duplicating machine having a printing drumrotatably supported between a pair of spaced side frames, apparatus forconnecting and disconnecting said drum comprising: axially alignedsupporting members rotatably journaled in said side frames; an opensleeve extending between ends of said drum along the rotational axisthereof; a first, manually actuated shaft supported by one of saidsupporting members for axial movement therein; a second, automaticallyactuated shaft supported by said sleeve for axial movement therein; theother of said supporting members having connecting means engageable withsaid second shaft when extended from said sleeve; said second shaftbeing movable through one end of said sleeve to engage said connectingmeans in response to movement of said first shaft into the other end ofsaid sleeve to thereby connect both ends of said drum to said supportingmembers; locking means for locking said shafts in connected position inresponse to rotation of said first shaft relative to said sleeve; a stopwithin said sleeve; and spring biasing means automatically urging saidsecond shaft toward said stop to a position wholly between the ends ofsaid sleeve in response to withdrawal of said first shaft from saidsleeve; whereby both ends of said drum can be connected or disconnectedsimultaneously in a single operation by manually moving said first shaftinto or out of said sleeve at one end of the drum.
 10. In a duplicatingmachine, the combination of claim 9 in which: each of said supportingmembers includes a mounting disc, said discs being parallel, coaxial andspaced apart to enable fitting of said drum endwise therebetween; and arotatable driving connection is provided between each said disc and anadjacent end of said drum including a radial rib and a pair ofcircumferentially spaced eccentric lugs, enabling said drum to beassembled between said discs, and to be disassembled therefrom, bymoving said drum transverse to the axis of rotation of the drum torespectively seat, and unseat, each rib between a corresponding pair ofsaid lugs; whereby said drum is centered relative to the discs by saidfirst and second shafts, and whereby rotational torque is transmittedfrom one disc to the other through the drum via the rotatable drivingconnections.
 11. In a duplicating machine, the combination of claim 9 inwhich: said sleeve and said first shaft have a screw-threaded connectiontherebetween; and said shafts are engageable before said screw-threadedconnection is engageable on inward movement of said first shaft; wherebyin connecting said drum between said sideframes said second shafT may beextended from said drum in two successive increments, namely, a straightaxial movement of said first shaft prior to engagement of saidscrew-threaded connection to thereby preliminarily extend said secondshaft from said sleeve, followed by rotation of said first shaft tofinally extend and lock said second shaft in extended position.